Hey girl. Before we go into the whole "if he loves me, he wont leave" kinda discussion. Answer this: what do you want?!
Simply as that, if you want to have a baby, then go ahead and be aware of the potential break up if he is not ready.
If you dont want a baby, then tell him so. Talk to him. And I mean communicate with him, ask him why he wants a baby now? And discuss what happens after the baby is born? Like discuss ur future with him. See if he actually has any plan at all or he is just dreaming.
Yea if he loves u, he wont leave, but how do we really know?!
I think the most important thing is what you want not what he wants.
And do not have that thought which "i have to have his baby coz I dont want him to leave me if I dont" that's the worst thought u could have! Dont have his baby to try to keep him, it never works